The present invention relates to testing heat pumps. More particularly, the present invention relates to testing a plurality of heat pumps simultaneously and under electronic control to ascertain if the heat pumps meet reference heat pump performance specifications.
An important part of the manufacturing process is the testing of the manufactured products to determine if they satisfy predetermined specifications. Generally, the specifications provide a range of acceptable values, and for a product to pass the testing, the test results for the product should be within the range of acceptable values.
As background to a discussion of a specific class of products, it is well known that heat spontaneously flows from a high temperature heat source to a low temperature heat sink. However, when it is desired to reverse this spontaneous process and have heat transferred from a low temperature heat source to a high temperature heat sink, then a heat pump must be employed.
An electric refrigerator is a form of a heat pump. An electric refrigerator generally includes five basic parts: (1) the receiver; (2) the refrigerant-control device; (3) the evaporator; (4) the compressor; and (5) the condenser. The receiver serves as the low temperature heat source which is cooled by the electric refrigerator. The room in which the electric refrigerator is located serves as a high temperature heat sink. The evaporator is run at a lower temperature than the low temperature heat source (the inside of the receiver) and receives heat from the low temperature heat source, thereby cooling the inside of the receiver. The condenser is run at a higher temperature than the high temperature heat sink and transfers heat to the high temperature heat sink, the room in which the refrigerator is located.
Relevant tests relating to the performance of an electric refrigerator can be concerned with the ability of the electric refrigerator to pump adequate amounts of heat out from the low temperature heat source, for a specified range of heat loads in the low temperature heat source, to maintain the low temperature heat source in a desired temperature range. If the electric refrigerator can maintain the low temperature heat source in the desired temperature range for the specified range of heat loads, then the electric refrigerator is adequate. On the other hand, if the electric refrigerator can not maintain the low temperature heat source in the desired temperature range for the specified range of heat loads, then the electric refrigerator is inadequate.
With respect to the testing of refrigeration systems, existing technology dictates that the critical parameters of a refrigeration system be manually recorded at specific points in time in relationship to the testing cycle in order to determine performance characteristics. Due to a system""s relatively low volumetric size, temperature changes occur very rapidly during the cool down and warm up cycles of a testing cycle. Inaccuracy in manual measurements can occur due to the occurrence of rapid temperature transitions as a result of a system""s dynamics and size. Moreover, manual testing of multiple refrigeration systems undergoing similar testing cycles simultaneously is virtually impossible. By the time a manual tester has finished taking a measurement on a first refrigeration system, it may already be too late to take a comparable measurement in a second refrigeration system. Results for manual testing of third, fourth, etc. additional refrigeration systems would be much too late and highly inaccurate.
The ability to test multiple refrigeration systems simultaneously is very important. When multiple refrigeration systems are manufactured, if the multiple refrigeration systems cannot be tested rapidly and accurately, the entire manufacturing process is impeded. If numerous employees are assigned the task of testing, so that testing can be completed promptly and accurately, testing costs would be unacceptably high and therefor uneconomical.
It would therefore be desirable if a testing apparatus and method were provided for heat pumps in general, and refrigeration systems in particular, wherein critical parameters are tested automatically and under computer control. Moreover, it would be desirable if such a testing apparatus and method were provided in which multiple heat pumps, in general, and multiple refrigeration systems, in particular, can be tested simultaneously.
The present invention satisfies, to a great extent, the need for testing a plurality of heat pumps simultaneously, under electronic control, and with automatic processing of test data. This result is achieved by the testing apparatus of the invention. In general terms, the testing apparatus of the invention includes an array of testing stations, wherein each of the testing stations includes at least one tester heat exchanger for attachment to at least one designated component of a selected heat pump. Each of the testing stations includes at least one temperature sensor for placing against the designated components of the selected heat pump. An array of data acquisition channels are in communication with the array of testing stations. Each of the data acquisition channels includes a data acquisition channel for each temperature sensor. A data logging system is provided which is in communication with the array of data acquisition channels. The data logging system monitors the temperature sensors and logs temperature readings versus time readings. Also, the data logging system computes heat pump performance information based upon the logged temperature and time readings. The data logging system can provide graphs which depict heat pump performance information versus time.
In addition, the data logging system can compare reference heat pump performance specifications with the computed heat pump performance information and can determine whether the selected heat pump for each testing station passes or fails the reference heat pump performance specifications.
Preferably, the array of testing stations is organized into groups of testing stations. Similarly, preferably, the array of data acquisition channels is organized into groups of data acquisition channels corresponding to the groups of testing stations. Each of the groups of data acquisition channels are organized into groups of multiple member data acquisition channels corresponding to the member testing stations. Each of the groups of member data acquisition channels include data acquisition channels for the temperature sensors.
Aside from monitoring heat pump performance during testing, the testing procedure can also include active control of the heat pumps undergoing testing. In this regard, each of the groups of testing stations can further include control devices for controlling operation of heat pumps associated with the member testing stations in each respective group of testing stations. In addition, groups of device control channels are provided, and each of the groups of device control channels includes device control channels for controlling the respective control devices in each of the respective groups of testing stations. Also, a device control system is provided for controlling the control devices.
Preferably, the data logging system and the device control system are combined in a programmable monitoring and controlling computer system. Also, preferably, the data acquisition channels and the device control channels are combined in a data acquisition and control system. Preferably, the data acquisition channels are analog channels, and the device control channels are digital channels, and the data acquisition and control system includes analog-to-digital converters for the analog channels.
Preferably, the data acquisition and control system includes a linear array of hook-up panels. The linear array of hook-up panels is grouped into groups of hook-up panels. Each of the groups of hook-up panels includes unit hook-up panels. Each of the groups of hook-up panels includes groups of controlling connector wires for connecting to respective tester heat exchangers and respective controlled portions of each heat pump under test. Each of the groups of hook-up panels includes groups of monitor connector wires for connecting to the respective temperature sensors for each heat pump under test. In this respect, preferably, each unit hook-up panel includes monitor connector wires for connecting to the respective temperature sensors for each heat pump under test and controlling connector wires for connecting to respective tester heat exchangers and respective controlled portions of each heat pump under test.
In more specific terms, this invention pertains to the specific design of an automated process control and testing system for the evaluation of performance characteristics of a stand alone refrigeration system. All critical parameters are monitored and compared to computerized, built-in pass/fail criteria. By applying specific evaporative temperature loads, and on completion of the automated testing protocol, the automated system issues a result-based temperature log designating system performance and indicating if the refrigeration system is in or out of compliance.
In another aspect of the invention, this invention pertains to the specific design of an automated process control and testing system for the evaluation of performance characteristics of a plurality of stand alone refrigeration systems. For each refrigeration system under test, critical parameters are monitored and compared to computerized, built-in pass/fail criteria. By applying specific evaporative temperature loads, and on completion of the automated testing protocol, the automated system issues a result-based temperature and time log designating system performance and indicating if the refrigeration system is in or out of compliance.
There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described below and which will form the subject matter of the claims appended hereto.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract included below, are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.